Methods and apparatus for dealing with pollution of waterways have historically experienced difficulty in the effective separation and subsequent holding, transportation and handling of the pollutant and/or contaminated material.
Some reasonably significant advances in the methods of disposal of pollutants once recovered have been made, however, a major difficulty remains in the actual separation of the pollutants (for example oils or other substantially non-soluble materials) from water, particularly where recovery is undertaken by way of pumping or other movement of the water/pollutant mix, or otherwise where a temporary emulsion is often created by agitation and where substantial quantities of unwanted water are also entrained in the pollutant recovery system. The mix volume often creates difficulty for transportation handling and disposal downstream.
Where the pollutant or contaminant is spread thinly over a wide area of waterway the actual volume of fluid (including both pollutant and water) required to be gathered in, contained, transported and subsequently separated and disposed of can be a ratio in the order of 1 to 100 of pollutant to water.
This adverse ratio can lead to high cost in the overall recovery process and therefore reduces the opportunity for pollution control often to a level where economic consideration take prime consideration over ecological ones.
Containment vessels or barges have been utilised to receive a pollutant and a mixture of water and pollutant. Generally, the discharge of the pollutant and any water therefrom has been somewhat haphazard and difficult, particularly when a cargo level is substantially low, such as when the vessel is decommissioned.
Attempts have been made to provide for the convenient lifting and subsequent drainage of vessels or barges after use, however in view of the weight of the barges or vessels, with even relatively small amounts of cargo remaining in a cargo area (and the need to avoid spillage of potentially pollutant material) drainage has been difficult to achieve without the need to resort to extremely robust vessel or barge construction, heavy duty cranes and the like.
It is therefore an object of this invention to overcome the above-mentioned problems or at least provide the public with a useful choice.